Clay is a big problem on Mars because it often forms in contact with water. Find clay, and you've usually found evidence of water. And the current nature, history and budget of water on Mars are all important to understand that planet, and if they ever sustained life.
At this time, MSL Curiosity is in Mt. Sharpening inspecting rocks for clay. The orbiters were the first to find evidence of clay in the bush. Acute. When NASA chose Gale Crater as the landing place of MSL Curiosity, the clay in Mt. Sharpening inside the crater was one of the objectives. Now Curiosity has taken samples from two of the rocks in what NASA calls "clay carrying unit" and have confirmed the presence of clay.
In fact, the two rocks show the highest concentrations of clay that Curiosity has found so far. The rocks are called "Aberlady" and "Kilmarie". They are located in the lower part of the mountain. Sharp, which is the main objective of the mission.
Mount Sharp rises 5.5 km (18,000 ft) above the crater floor, which means it is an accessible and layered record of Martian geology. Over time, the wind has exposed its different layers, which makes them easy targets for the Curiosity exercise.
Scientists are interested in Mt. Sharp, also called Aeolis Mons, because of how they think it was formed. The Gale crater is an old impact crater that was probably full of water, and they think the mountain. Sharp was formed over a period of two billion years, since the sediments were deposited at the bottom of the lake. It is possible that at some point the entire crater was full of sediments, which gradually eroded, leaving the mountain. Sharpened from behind.
There is some uncertainty around the timeline of Mt. Sharp's training, which is one of the things that MSL Curiosity hopes to discover. In any case, Mt. Sharp itself seems to be a mountain eroded by sediment, and as Curiosity continues its work, scientists can finally have a clearer idea of exactly how it was formed.
Curiosity's new findings show that there was once an abundance of water in the Gale crater, as expected. But apart from that, the details have yet to be determined. It seems that these clay-rich rocks in the lower range of the mountain formed as sediments at the bottom of a lake. Throughout geological periods, water and sediments interact to form clays.
Finding specific types of clays in specific layers tells scientists about the Martian water timeline. We know that the mountain has different layers that contain different minerals. As mentioned, the lower layers contain clays, but on these layers there are layers that contain sulfur, and above there are layers that contain minerals that contain oxygen. Sulfur indicates that the area dried or the water became more acidic.
The Gale crater also contains a river channel called Cbad Gediz Vallis, which was formed after the layers of clay and sulfur. That channel is also a piece of the puzzle, and Curiosity's task is to continue on its way to the Mount. Sharp, sampling as you go, and complete the picture of the geology and history of the mountain. By extension, we will learn something about the history of Mars.
Curiosity will also give us a much more detailed view of the unit with clay than the one the orbiter gave us. The orbital readings could not say with certainty if the clay he felt was in the rock of the mountain, or if it was from rocks and eroded rocks that had eroded from the upper layers of the mountain and fell to the floor of the crater. Curiosity has clarified it to a certain extent, with the discovery of clay in Aberlady and Kilmarlie, but there is still much work to be done.
"Each layer of this mountain is a piece of puzzle," said curiosity project scientist Ashwin Vasavada of JPL. "Each of them has clues from a different era in the history of Mars."
Curiosity is doing a good job of putting everything together.